The Visual Time Sheet software can be installed on a company's server and configured for multiple users. Each user have full access to the data from the server database. Also, using a configure utility available for this software, you can assigned special attributes for every user (some users can only read the data while others can administer it by adding or deleting entries). For more information regarding the first 3 questions you can visit the following official website.
The software can be downloaded in a trial version that is available for 30 days.